Tubing anchor



PAGE

TUBING ANCHOR Filed July 11, 1942 H/JA To may Inventor dorm 5. PAGEPatented Oct. 26, 1943 2,332,749 TUBING ANCHOR John S. Page, Long Beach,Calif., assignor of onetenth to Betty Lee McLaughlin, Los Angeles,

Calif.

Application duly ll, 19d2,$erial No. M0516 V M (Claims.

This invention has to do with well equipment and has more particularreference to tubing anchors. A general object of this invention is toprovide a simple, practical and very efiective tubing anchor.

When an oil well or the like is equipped with a pump it is customary toinstall a string of tubing in the well to carry the pumped fluid to theground surface and to arrange the pump at the lower end of this tubing.The long string of tubing has substantial flexibility and elasticity andduring operation of the pump the tubing works up and down. This workingof the tubing is caused by movement of the fluid column within thetubing, by the friction between the relatively reciprocable pump plungerand pump barrel and by the alternate imposition and relieving of theweight of the fluid column on the pump, which accompanies thepump-operating movements of the pump rod. The movement or working of thetubing produces wear between the tubing and the well casing and oftencauses holes to be worn in the casing and also wears the couplings ofthe tubing string so that they leak and sometimes fail.

Another object of this invention is to provide a tubing anchor thatefiectively prevents working of the tubing.

Another object of this invention is to provide a tubing anchor thatserves to maintain the tubing under tension or in a stretched conditionso that it cannot stretch further and cannot contract during the pumpingoperations. When a conventional tubing anchor is used the tubing isrelieved of a portion of its weight there by causing slack in the tubingand allowing the above described working of the tubing. Where the tubinganchor of the present invention is employed the tubing is held undertension so that there is no slack and no possibility for the tubing towork.

Another object of this invention is to provide a tubing anchor that isactuated and held actuated by the head or hydrostatic pressure of thecolumn of fluid in the tubing and that is released or conditioned forready release when the fluid column is drained from the tubing. Nomanipulation of the tubing string is required for either the operationor the release of the anchor of this invention. The operation of theanchor is entirely automatic and the tubing need not be disturbed tocontrol or operate the anchor.

Another object of this invention is to provide a tubing anchor that ispositive in operation and that remains positive and effective so long asthe fluid column occupies the tubing string.

Another object of this invention is to provide a tubing anchor of thecharacter referred to that is extremely simple in construction and thatis not subject to becoming "sanded up or made inoperative byaccumulations of sand.

A further object of this invention is to provide a tubing anchor of thecharacter mentioned that does not restrict or in any way interfere withthe movement of fluid through the tubing and that may be interposed inthe tubing string at any selected point or points without necessitatingalteration of the tubing string assembly.

The various objects and features of my invention will be fullyunderstood from the following detailed description of a typicalpreferred form and application of my invention, throughout whichdescription reference is made to the accompanying drawing, in which:

Fig. 1 is a side elevation of the improved anchor of this invention inposition in the well tubing prior to actuation. Fig. 2 is an enlargedlongitudinal detailed sectional View taken substantially as indicatedbyline 22 on Fig. 1, showing the anchor in the actuated condition andFigs. 3, 4 and 5 are transverse detailed sectional views taken asindicated by the line 3--3, 4-4 and 5--5, respectively, on Fig. '2.

In the drawing, C designates the well casing and T designates a portionof the well tubing extending through the casing. It will be assumed thatthe tubing T extends from the well pump, not shown, to the top of thewell where it may be secured to the usual tubing head. The anchor of theinvention may be connected in the string of well tubing T at anyselected or desired point and, if desired, two or more of the anchorsmay be incorporated in the tubing string at vertically spaced points.

The tubing anchor of this invention may be said to comprise, generally,a tubular body In to be connected in the tubing string T, means II onthe body for gripping the casing C and means l2 for operating thegripping means II.

The body l0 serves to carry or mount the various other parts of the tooland, in accordance with the invention, is a simple unit that may bereadily interposed in the string of tubing T. The body I0 is an elongatetubular structure or member. In the particular case illustrated the bodyl0 comprises two sections [3 and I4, it being understood that the bodyI0 may be an integral element if desired or found practical. The upperand lower sections l3 and H are connected by a suitable threaded collaror coupling II. The longitudinal opening l8, extending through thetubular body sections i3 and I4, is preferably of the same diameter orfluid capacity as the opening in the tubing string T so that the bodyoflers no resistance or obstruction to the fluid flow and does notinterfere with pump rod movement. In the case illustrated the opening Itin the upper body section I! is enlarged at its upper end and isscrew-threaded so that the body section l3 may be directly screwed ontothe tubing T. The lower portion of the lower body section I4 is enlargedto have, what I will term. a chamber l1. An adaptor or sub l8 may bescrewthreaded into the lowerend of this chamber i1 and may be screwedinto a'boiiiSllng'N'Bf the tubing T to secure the lower end of the bodyIn in the tubing string. The enlarged lower portion of the body sectionl4 just referred to has a flange or wall 20 of substantial verticalextent or thickness. This wall 20 occurs at the upper end of the chamberi1 and its function will be later described. The exterior of theenlarged lower portion of the body l may be provided withcircumferentially spaced grooves or channels 9 to provide for the freepassage of fluid. It will be observed that the body Ill just describedis a simple inexpensive structure.

The means II is provided to grip the casing C to hold the tubing Tagainst movement and more particularly is operable to maintain thetubing T under tension so that it cannot work up and down duringoperation of the well pump. The means II is in the nature of a wedgemeans or slip means and comprises two or more spaced wedge abutments orwedge faces 2| on the body II). In the preferred arrangement the means His carried on the upper body section l3 and there is a. plurality ofspaced wedge faces 2|. The body section it is provided withcircumferentially spaced vertical or longitudinally extending ribs 22whose outer surfaces are pitched or sloped to constitute the slipactuating faces 2|. As best illustrated in Fig. 3 of the drawing, theribs 22 are spaced apart to leave ample fluid passages between them. Itis preferred to provide the slip faces 2| with dove-tailed splines orribs 23.

The casing gripping means ll further includes slips 24 which cooperatewith the inclined faces 2!. The slips 24 are wedge parts having slopinginner surfaces which cooperate with the inclined faces 2| and havingroughened or toothed outer sides curved to conform to the internalsurface of the casing C. The pitched or inclined inner sides of theslips 24 are provided with dovetailed or undercut grooves 25 whichslidably receive the tongues 23 to retain the slips in slidingcooperation with the faces 2|. The outer or active faces of the slips 24preferably have teeth 26 for gripping with the internal surface of thecasing C. In accordance with the invention the teeth 26 face upwardlyand outwardly so that they are particularly effective in gripping thecasing C to prevent upward movement of the tubing T. In this connectionit is to be observed that the slips 24 have teeth of a different patternor disposition than conventional slips. Conventional slips have teethwhich are pitched in the opposite direction to their sloping innersides. In the present invention the teeth 26 are pitched in the samegeneral direction as the inclined inner sides of the slips 24 to holdthe tubing T against upward movement.

The gripping means H preferably includes means for operativelyconnecting the several slips 24 for simultaneous operation. This meansmay include a tube or sleeve 21 shiftably or slid- I ceived by the pairsof spaced lugs 22 d 22 and pivot pins II and 22 carried by the lugs passthrough openings in the links to pivotally connect the links with theslips and sleeve. It will be seen how the links 20 connect the several814p! 24 with the sleeve 21 for simultaneous vertical movementtherewith, while allowing free radial projection and retraction of theslips.

It is preferred to provide the tool with means for yieldingiy holdingthe slips 24 in the retracted positions so that the anchor may be rundown through the casing on the tubing '1' without interfering with thecasing, which means also aids in retracting the slips when the tubing '1is to be withdrawn from the well. This means is preferably associatedwith the sleeve 21 to hold the sleeve in a position where the pluralityof slips is retracted. The means for yieldingly holding the slips 24retracted includes a spring 23 surrounding the body section l4 andhoused within the sleeve 21. The internal diameter of the sleeve 21 isreduced adjacent the lower end of the sleeve providing an upwardlyfacing internal shoulder 24. The major portion of the sleeve 21surrounds the body section I 4 with considerable clearance and engagesover the collar II with suitable working clearance. The spring a ishoused or received within the sleeve 21 and is arranged undercompression between the shoulder 34 and the lower end of the coupling orcollar ii. The spring 32 acting downwardly against the shoulder 24yieldingly urges the sleeve 21 to the position where the slips 24 areretracted as shown in Fig. 1 of the drawing. It will be observed thatthe spring 22 is effectively housed and protected in the sleeve 21. Thesleeve 21 engages about the body section l4 and collar II withsuflicient clearance so that there is no dashpot action accompanyingmovement of the sleeve which might retard retraction or expansion of theslips 21, as the case may be.

The means [2 is a fluid pressure actuated means being operable by thehydrostatic pressure of the column of fluid within the tubing string'1". The means l2. when actuated, is operable to hold the tubing '1against movement and. as will be later described, serves to hold thetubing string under tension, that is. it operates to prevent upwardmovement of the tensioned tubing. In accordance with the invention themeans l2 includes one or more cylinders 22 and pistons 28 operabletherein. In the construction illustrated one or more cylinder openings2! are formed in the wall 20. With the particular construction disclosedthere are three circumferentially spaced vertical cylinder openings 28axially aligned with the ribs 22 and slips 24, it being understood thatthere may be any selected or required number of cylinder openings spacedand arranged as found most desirable. The cylinder openings 25 may beplain cylindrical openings of uniform diameter extending upwardly fromthe chamber ll to the upper end of the wall 20. A piston 36 operates ineach cylinder opening 35. The pistons 36 may be solid cylindricalmembers of sufficient length to extend completely through the cylinderopenings 35 and project from the end of the openings when in theunactuated positions. It is preferred to provide the pistons 36 withsealing rings 31 formed to efiectively seal with the Walls of thecylinder openings 35.

The upper ends of the pistons 36 are operatively associated or engagedwith the sleeve 21. In the simple construction illustrated the upperends of the pistons 36 have heads 38 presenting fiat faces which engageupwardly against the lower end of the sleeve 27. The sleeve 21 may havebosses or enlargements 39 adjacent its lower end to have completeengagement with the piston heads 38. The pistons 36 are formed andproportioned so that the sealing rings 37 never leave the cylinderopenings 35 and the heads 38 are engageable with the wall to limitdownward movement of the pistons. In accordancewvith the invention thepistons 36 are of sufficient length to either project into the chamberIT or to have their lower ends flush with the upper wall of the chamberll when the pistons and slips M are in the fully actuated positions.With the pistons 36 engaged in the cylinder openings 35, as justdescribed, the lower ends of the pistons are exposed to the hydrostaticpressure existing in the tubing T under normal pumping conditions andthis pressure acts upwardly on the pistons to maintain them in thepositions illustrated in Fig. 2 of the drawing where the slips 2 arefully actuated.

In the use or operation of the tubing anchor provided by this inventionthe anchor is interposed in the string of tubing T at the selected pointwhen the tubing is assembled and run into the Well. The tubing T may becompletely assembled and run into the well and its upper end may bebolted or otherwise secured to the usual tubing head at the groundsurface. The well pump, not shown, is then run in on the sucker rod orpump operating rod. In the preferred mode of employing the invention thefull weight of the pump and the string of pump rods is imposed on thetubing. The combined weight of the pump and the pump rod applied to thetubing '1 adjacent its lower end elongates or stretches the tubing,putting the tubing under tension. It will be assumed that the pumpingassembly includes the usual foot valve which prevents the discharge offluid from the lower end of the tubing. When the pump has been seated asabove described the string of tubing T is filled with fluid. The weightof the long column of fluid thus provided in the tubing T subjects thetubing to further elongation and tensioning. It is to be observed thatwhen the string of tubing T is subjected to the combined weight of thepump, the string of pump rod and the complete fluid column that it issubjected to a greater tensioning force than at any time duringsubsequent pumping operations. Filling of the tubing T with liquid asjust described, is accompanied by automatic operation of the slips 24.

As the column of liquid builds up in the tubing T the pistons 36 aresubjected to increasing hydrostatic pressure. When the tubing iscompletely filled the pistons 36 are subjected to the maximumhydrostatic pressure and will have been actuated upwardly to expand theslips 24 into tight gripping engagement with the casing C. It will beseen how the hydrostatic pressure acting upwardly against the pistons 36moves the pistons, the sleeve 21 and the slips 24 upwardly. Upwardmovement of the slips 24 along the inclined faces 2| produces outwardmovement or expansion of the slips and causes the slips to tightly gripthe internal surface of the casing C. Thus, the slips 24 are fully andefiectively operated into tight gripping engagement with the casing Cwhen the string of tubing '1 is stretched and elongated to the maximumextent.

Following the actuation of the slips 24, as just described, the pumpoperating rod may be pulled upwardly to "space the pump and the usual orregular Dumping operations may be carried on. The raising of the pumprod removes a substantial part of the load or weight from the tubing Tand the tubing tends to contract. However, the slips 25 being held intight gripping engagement with the interior of the casing C prevent thiscontraction of the tubing T and maintain the tubing under tension.During the pumping operations the movement of the fluid column in thetubing T, the friction at the pump and the pump rod movement will tendto cause moving or "working of the tubing T. However, the slips 2t beingin tight gripping engagement with the casing C and engaged between thecasing and the ribs 22 dependably hold th tubing T against such movementor working. So long as the tubing T is maintained under tension throughthe gripping action of the slips 24 there can be little or no movementor working of the tubing. Accordingly, the tubing and the casing C arenot subjected to the wear which usually accompanies the Working of thetubing.

When it becomes necessary or desirable to withdraw the tubing T from thewell the column of liquid is drained from the tubing. This results inthe automatic release of the slips 2B. When the liquid is drained fromthe tubing T the hydrostatic pressure is removed from the pistons 36 andthe pistons are free to return to their unactuated positions. The weightof the sleeve 21, links 30 and slips 2% assisted by the spring 33automatically retracts the slips 24. The dove-tailed splines 23 andgrooves 25 assure positive retraction of the slips. Because the slip 24are freed or released automatically upon draining of the tubing '1 thetubing may be pulled from the well immediately following the drainingoperation and no manipulation of the tubing is required to release theanchor. In this connection it is to be observed that the operation ofthe anchor is entirely automatic, that is, it is unnecessary tomanipulate or operate the tubing T in order to actuate the anchor or torelease the anchor.

The invention contemplates that the anchor may be employed either in theposition illustrated in the drawing or in an inverted position. With theanchor employed in the position illustrated in the drawing there isabsolutely no danger of the slips 24 interfering with the freewithdrawal or pulling of the tubing T subsequent to draining of thetubing. With the anchor inverted from the position illustrated in thedrawing it is necessary that the tool be constructed so that the slips24 will be positively retracted from the casing C when the tubing T isdrained. Such positive retraction of the slips 24 may be effected by thespring 33 or the equivalent.

Having described only a typical preferred form and application of myinvention, I do not wish to be limited or restricted to the specificdetails herein set forth, but wish to reserve to myself any variationsor modifications that may appear to those skilled in the art and fallwithin the scope of the following claims.

Having described my invention, I claim:

1. In combination. a well tubing, and an anchor for the tubingcomprising a tubular body adapted to be interposed in a well tubing,slip means carried by the body for gripping the wall of the well to holdthe body and tubing against upward movement, and means adapted to beactuated by the hydrostatic pressure of a column of fluid in the tubingfor operating the slip means.

2. A tubing anchor for anchoring a string of well tubing in a wellcomprising a tubular body, connecting means for connecting the body inthe string of well tubing, wedge slip means carried by the body forgripping the well casing to hold the tubing string against upwardmovement, and cylinder and piston means on the body actuated by thehydrostatic pressure of the column of fluid in the tubing for operatingthe slip means.

3. A tubing anchor for anchoring a string of well tubing in a wellcomprising a tubular body, connecting means for connecting the body inthe string of well tubing, a part on the body having an inclinedsurface, a gripping slip operable into engagement with the well casingthrough movewent along said surface, and means operable by thehydrostatic pressure in the tubing for holding the sli in the positionon said surface where it grips the well casing to hold the tubingagainst upward movement.

4. A tubing anchor for anchoring a string of well tubing in a wellcomprising a tubular body, means for connecting the body in the stringof well tubing so that the opening of the tubular body forms a part ofthe passage through the tubing string, a part on the body having aninclined surface, a gripping slip operable into engagement with the wellcasing through movement along said surface. and means adapted to beoperated by the hydrostatic pressure in the tubing for holding the slipin the position on said surface where it grips the well casing to holdthe tubing against upward movement, said means comprising a cylinder inthe body having communication with the interior thereof, and a piston inthe cylinder operatively associated with the slip.

5. A tubing anchor for anchoring a string of well tubing in a wellcomprising a tubular body, means for connecting the body in the stringof well tubing, the body having a chamber in communication with theinterior of the tubing and a cylinder opening in communication with thechamber, a part on the body having an inclined surface, a slip operableoutwardly into gripping engagement with the casing when moved along saidsurface, and a piston operable in said opening by the hydrostaticpressure in the tubing for moving the slip along said surface to actuate.a part on the body having an inclined surface,

a gripping slip operable into engagement with the well casing throughmovement along said surface, cylinder and piston means on the bodyoperable by the hydrostatic pressure in the tubing passage for movingsaid slip along said surface, and spring means for retracting said slipwhen the hydrostatic pressure is reduced.

7. A device for anchoring a string of well tubing in a well casingcomprisinga tubular body, means for connecting the body in the tubingstring to form a part thereof, the body having inclined surfaces, slipsoperable along said surfaces to grip the casing, a sleeve shiftable onthe body and operatively connected with the slips, the body having aplurality of cylinder openings in communication with the interior of thetubing, and pistons in said openings operable by the hydrostaticpressure in the tubing to move the sleeve and thus actuate the slips togrip the casing and hold the tubing against upward movement.

8. A device for anchoring a well tubing in a well casing comprising atubular body adapted to be interposed in the tubing, the body havinginclined surfaces, slips operable along said surfaces to p the casing, asleeve shiftable on the body and operatively connected with the slips,the body having one or more cylinder openings in communication with theinterior of the tubing, and pistons in said openings operable by thehydrostatic pressure in the tubing to move the sleeve and thus actuatethe slips to grip the casing, the weight of the slips and sleeve tendingto move the slips to retracted positions when the hydrostatic pressuredrops.

9. A device for anchoring a well tubing in a well casing comprising atubular body adapted to be interposed in the tubing, the body havinginclinedv surfaces, slips operable. along said surfaces to grip thecasing, a sleeve shiftable on the body and operatively connected withthe slips, the body having one or more cylinder openings incommunication with the interior of the tubing, pistons in said openingsoperable by the hydrostatic pressure in the tubing to move the sleeveand thus actuate the slips to grip the casing, and spring means forretracting the slips when said hydrostatic pressure drops.

10. A device for anchoring a well tubing in a well casing comprising atubular body adapted to be interposed in the tubing, the body havinginclined surfaces, slips operable along said surfaces to grip thecasing, a sleeve shiftable on the body and operatively connected withthe slips, the body having one or more axial cylinder openings incommunication with the interior of the tubing, and pistons in saidopening operable by the hydrostatic pressure in the tubing to push saidsleeve axially of the body and thus move the slips along said surfaces.

11. A device for anchoring a well tubing in a casing comprising atubular body to be interposed in the tubing, the body having a chambercommunicating with the interior of the tubin and axial cylinder openingsleading from the chamber, spaced sloping parts on the exterior of thebody, slips operable along said parts to be moved into grippingengagement with the casing, a sleeve shiftable on the body, operativeconnections between the sleeve and slips, and pistons operable in saidopenings to move the sleeve and thus operate the slips along said parts.

12. A device for anchoring a well tubing in a casing comprising atubular body to be interposed in the tubing, the body having a chambercommunicating with the interior of the tubing and axial cylinderopenings leading from the chamber, spaced sloping parts on the exterioroi the body, slips operable along said parts to be moved into grippingengagement with the casing, a sleeve shittable on the body, operativeconnections between the sleeve and slips, a spring in said sleevereacting between the body and sleeve to yieldingly hold the sleeve in aposition where the slips are free of the casing, and pistons operable insaid openings to move the sleeve and thus operate the slips along saidparts.

13. A device for anchoring a well tubing in a casing comprising atubular body to be interposed in the tubing, the body having a chambercommunicating with the interior of the tubing and axial cylinder openingleading from the chamber, spaced sloping parts on the exterior of thebody, slips operable along said parts to be moved into grippingengagement with the casing, a sleeve shiitable on the body, operativeconnections between the sleeve and slips, and pistons operable in saidopenings to move the sleeve and thus operate the slip along said parts,the pistons projecting into said chamber at all time to prevent sandingup of the cylinder openings.

14. A device for anchoring a well tubing in a casing comprising atubular body to be interposed in the tubing, the body having a chambercommunicating with the interior of the tubing and axial cylinderopenings leading from the chamber, spaced downwardly and inwardlysloping parts on the exterior of the body, slips operable along aidparts to be moved into gripping engagement with the casing, upwardly andoutwardly facing teeth on the slips for gripping the casing, a sleeveshiftable on the body, operative connections between the sleeve andslips, and pistons operable in said openings to move the sleeve and thusoperate the slips along said parts.

. JOHN 5. PAGE.

